Anti-RSPO1 (R-Spondin 1, Roof Plate-specific Spondin-1, hRspo1)

R-Spondin 1 (RSPO1, Roof plate-specific Spondin 1), also known as cysteine-rich and single thrombospondin domain containing protein 3 (Cristin 3), is a 27kD secreted protein that shares 40% aa identity with three otherR-Spondin family members (1, 2). All R-Spondins regulate Wnt/b-catenin signaling, but have distinct expression patterns (1-3). Like other R-Spondins, R-Spondin 1 contains two adjacent cysteine-rich furin-like domains (aa34-135) with one potential N-glycosylation site, followed by a thrombospondin (TSP-1) motif (aa147-207) and a region rich in basic residues (aa211-263). Only the furin-like domains are needed for b-catenin stabilization (2, 4). A putative nuclear localization signal at the C-terminus may allow some expression in the nucleus (5). Potential isoforms of 200-236aa have an alternate, shorter N-terminus or are missing aa146-208, respectively (6). Over aa21-263, human R-Spondin 1 shares 89%, 87%, 92%, 91%, 91% and 89aa identity with mouse, rat, equine, canine, caprine and bovine R-Spondin 1, respectively. R-Spondin 1 is expressed in early development at the roof plate boundary and is thought to contribute to dorsal neural tube development (3, 5). In humans, rare disruptions of the R-Spondin 1 gene are associated with tendencies for XX sex reversal (phenotypic male) or hermaphroditism, indicating a role for R-Spondin 1 in gender-specific differentiation (7, 8). Disruption is also associated with palmoplantar keratosis (7, 8). Postnatally, R-Spondin 1 is expressed by neuroendocrine cells in the intestine, adrenal gland and pancreas, and by epithelia in kidney and prostate (9). Injection of recombinant R-Spondin 1 in mice causes activation of b-catenin and proliferation of intestinal crypt epithelial cells, and ameliorates experimental colitis (9, 10). R-Spondin 1 regulates Wnt/b-catenin by competing with the Wnt antagonist DKK-1 for binding to the Wnt co-receptors, Kremen and LRP-6, reducing their DKK-1-mediated internalization (11). Reports differ on whether R-Spondin 1 binds LRP-6 directly (11-13). Applications: Suitable for use in Neutralization. Other applications not tested. Recommended Dilution: Optimal dilutions to be determined by the researcher. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.